1. Field of the Invention
The present invention relates generally to a system for monitoring the state-of-charge and state-of-health of batteries.
2. Discussion of the Related Art
The requirement for monitoring the health of batteries has been in existence, perhaps, for as long as the batteries themselves. Over the past several decades, numerous instruments and devices that purport to monitor the health of batteries have been used. Some of these devices are based on the measurement of the battery electrolyte specific gravity and others rely on the measurement of the battery voltage with and without a load. The relatively more complex instruments record the current and voltage, and/or coulombs of electric charges during the charging and discharging periods. Difficulties and deficiencies associated with these instruments include large mass, volume and power consumption, high complexity and cost, and measurement inaccuracies. Thus there is a need for an apparatus for monitoring the health of battery that is relatively small and light, low in power consumption, complexity and cost, and that provides accurate information about the state-of-charge (SOC) and state-of-health (SOH) of batteries. Note that the SOC indicates the useful operating time available in a battery following charging and partial use. SOH indicates the available life of a battery following its use after manufacturing.